Batkid's Make-a-Wish Transforming San Francisco Into Gotham

A little boy will get the surprise of a lifetime today when San Francisco transforms into Gotham City to fulfill the 5-year-old leukemia patient's wish to be Batman for a day.

The Make-a-Wish Foundation has created an entire day catered to Miles' dream.

The day has begun with a special edition cover of the San Francisco Chronicle, whose entire front page is dedicated to the young superhero. The headline for the lead story is "Batkid Saves City."

The author? None other than Clark Kent.

The other front page stories, all about Batkid, are written by Lois Lane, Brenda Starr and Perry White.

Around 9:30 a.m. PT, Miles will see a breaking news story on a TV. The police chief will be asking whether anyone knows where Batkid is because he needs his help to solve a crime and "bringing the bad guys to justice," Make-a-Wish said in a statement.

Miles' day will then include rescuing a damsel in distress tied up across the Hyde Street cable car line and capturing the Puzzler in the act of robbing a downtown vault. As Batkid eats his lunch at Burger Bar, he'll get a special message from the chief, telling him to go to the window where he'll look out over Union Square and see a huge group of volunteers jumping up and down and asking for his help.

A villain will be kidnapping a famous San Francisco mascot and Batkid will rush to the rescue. His last stop will be City Hall, where the mayor and police chief will thank him and present him with a key to the city and a crowd will be cheering him on.

"He is a sunny, positive little boy and finds his inspiration in super heroes," Make-a-Wish said of Miles. "When we interviewed Miles for a wish, he surprised even his parents: he wishes to be BatKid!"

Make-a-Wish decided to make Miles' dream come true and, in a rare move for the foundation, asked the public to participate.

"This is one that we thought of as a great opportunity for people to share in the power of a wish so they can see how it affects not only the children and their families, but also the other people involved," Jen Wilson, marketing and promotions manager for Make-a-Wish in San Francisco, told ABCNews.com. "It has a big impact on many people.

"Since he wants to be a superhero, we felt like having a large crowd there waiting with signs and cheering him on would make him feel like a hero, not just because he battle villains and helped fight crime, but he's a true hero," Wilson said.

The interest level in Miles' wish has been "extreme," Wilson said, and that this is "definitely not the typical wish we grant."

The group is expecting hundreds, and possibly thousands, of people to come out and participate.

"We've gotten people who want to volunteer to participate, actors reaching out asking if they can play a role, photographers and videographers offering their services, people who want to give Miles gifts, makeup artists willing to donate their services, a fire truck that want to come out and show their support," Wilson said. "It's quite a range."

ABCNews.com will be following Batkid throughout the day, so check back for more.